Since undergoing surgery in January for a partially torn labrum in his throwing shoulder, the star quarterback missed all of Indy's offseason workouts, all of training camp, the entire preseason and will miss his ninth straight regular-season game Sunday at Houston.

Luck didn't even start throwing to teammates until early October and was shut down two weeks later after complaining of soreness in his right shoulder.

So with the Colts (2-6) struggling, their playoff hopes fading fast and Luck apparently not close to 100 percent, Indianapolis made the smart move.

"He was frustrated. He's a competitive guy, he knows the impact he has on a Sunday," Ballard said. "He's a difference-maker. He's one of the best quarterbacks in the league, so he's frustrated."

Ballard said Luck will do his rehab at a couple of different places and is expected to be in and out of the team complex and that they will take a different approach with rehab for his strength.

Ballard said the Colts have to be patient in letting Luck work through this.

As for putting his career in jeopardy, Ballard said: "I'm not getting career-ending from anybody. What we're getting is 'be patient.' Career-ending is putting him on the field before he's ready to play."

If Luck is ready to go for the 2018 season opener, Luck would go more than 20 months between taking regular-season snaps.

Dr. Amin Tehrany, an orthopedic surgeon who specializes in shoulders and knees and is a founder of Manhattan Orthopedic Care in New York, doesn't believe the length of the recovery should set off alarms.

"It's a little unusual," said Tehrany, who hasn't examined Luck. "The question is how severe was the injury, how much surgery was required and what type of surgery was required. He also seems to have had the injury for a long time, two years. When the complaints of the injury linger for a long time, the recovery takes longer."

Perhaps the Colts are simply sticking to their long-term plan.

Throughout the process, Ballard has said Luck wouldn't be rushed back for any reason.

That's put coach Chuck Pagano in a sticky situation. He appears to be fighting to keep his job after posting back-to-back 8-8 records without going to the playoffs. Luck missed nine games in 2015 and one in 2016.

Just three weeks ago, even Luck was optimistic his long road back was nearing its end.

"There has been an effort not to skip steps (during the rehab)," Luck said Oct. 12. "I think we're progressing along with the plan nicely, and it would be foolish to get close to the finish line and start skipping steps."

Six days later, Ballard told reporters that Luck had received a cortisone shot to deal with inflammation in the shoulder.

At the time, Ballard called it a normal part of the recovery process and said when Luck was cleared to resume throwing, he would pick up right where he left off.

Instead the soreness lingered and Luck eventually started visiting additional doctors to get answers.

In the meantime, Jacoby Brissett continued to replace Luck in the lineup and the Colts continued to search for backups. Four quarterbacks worked out Tuesday at the team's complex.

With Luck out, Indy is likely to add at least one quarterback to back up Brissett and opening day starter Scott Tolzien.

"You have to be smart," running back Frank Gore said earlier this week. "I just think he should be smart and do what's right for him. If he can go, he's going to go. I know what he's done here. I don't question that. But I think he should be smart, and he's a young player, a great player."

A healthy Luck led the Colts to the playoffs each of his first three years in the league and took them a step deeper in the playoffs each season, too. He also was sacked 100 times in those three seasons, hits that finally started to take a toll on Luck's body in 2015.

Luck missed two games after hurting his right shoulder at Tennessee on Sept. 27, 2015, returned for four and then missed the last seven with a lacerated kidney.

Rather than have offseason shoulder surgery then, Luck opted for rest. In June 2016, he signed the richest contract in NFL history — six years, $140 million with $87 million guaranteed.

Pagano diligently tried to protect the Colts' big investment by giving him extra days off during the week last season.

Luck responded with one of the best statistical seasons of his career — completing a career-best 63.5 percent of his passes, finishing with 4,240 yards, 31 touchdowns and 13 interceptions.

But because Luck thought the shoulder was still inhibiting his play, he opted for the surgery.

Now, he's likely done for the season and the questions will linger beyond next year's draft when the Colts could have a top-five pick.

"I think because he's had a pain for a couple years," Tehrany said, "it will take a longer time for recovery."